Pruning young minds

Published online on Sunday, Sep. 28, 2008

I've discovered why my teenage son doesn't clean up his room: His brain won't let him.

Neurologists have discovered that from ages 11 to 14, teenagers lose a substantial fraction of connections between brain cells. Neural connections or synapses get pruned out, according to Jay Giedd, child development specialist at the National Institute of Mental Health.

It's part of growing up, the brain prunes unneeded wiring from childhood to make way for efficient adult level connections. As a result, young teenagers can't help it, their brain is changing, and this may contribute to an inability to make clear and good decisions.

I know it may sound like another excuse from a teenager, but this is part of new research on the brain's transformative stages of learning development. Specifically, researchers are studying the transition from a childlike understanding of the world toward maturity and the ability to cope with adult level decision-making.

Me, too. I want to figure that one out. I would love to learn why it seems like teenagers don't listen (at least to me). Why they have more car accidents -- is it just lack of experience?

I'd also apply this to exploring critical issues affecting society -- alcohol and drug abuse, teen pregnancy. Is it correct to say teenagers are less mature than adults?

Alison Gopnik, child development scientist at the University of California at Berkeley, says that in the brain during teen years, ineffective connections get pruned out, like a gardener reshaping a tree or bush.

Synapses not needed wither and die, but those that are used survive and flourish. Meanwhile, the frontal lobes of the brain -- where areas of judgment, organization, planning and strategizing -- are found to develop during these teen years. The fundamental pathways between different parts of the brain are being built as a foundation.

Scientists claim this synaptic pruning is good. It improves the speed of information processing and makes the brain more efficient. The brain is reorganizing itself as the maze of neural connections are hardwired for adult life. The brain is growing more efficient.

While not proven, I believe when developing teenagers are exposed to art, music and academics, their synapses grow thick into multilane superhighways, capable of handling a crush of information and avoiding traffic jams.

If fed a steady diet of video games, TV and passive entertainment, those connections are narrow lanes, easily blocked. A teenager becomes an expert at guitar hero decision-making, but poor at managing information from a history class.

Girls typically start pruning brains a year ahead of boys. From my own observations, I know this well. My own teenage son has a favorite answer for everything: "Fine." A friend, though, said we were lucky. At least our son talks.

I am not an expert in neurological science, but I have witnessed changes in teenage attitudes. Something happens when a sweet, young child enters puberty. They often suddenly become moody, reacting with their gut. They can't express themselves in an organized way. Instead, they lead with their emotions.

These are changes that teenagers may not understand. Their brains are rearranging themselves and what may seem a logical explanation eludes them. Parents and adults often can't comprehend why they're suddenly the enemy.

In a way, teenagers may be going through a mid-life crisis. The old systems of viewing the world from the eyes of a child are no longer valid. Teenagers have a senior moment, unable to come up with the words that explain. And this is all natural.